Don't repeatedly upgrade to python3

src/freedombone-app-matrix

@@ -538,22 +538,24 @@ function upgrade_matrix {
     export TMPDIR=/etc/matrix/tmp
 
     # install python3 packages
-    if [[ "$MATRIX_PYTHON" != '/usr/bin/python' ]]; then
-        if [ -d /usr/local/lib/python3.5/dist-packages/pip ]; then
-            rm -rf /usr/local/lib/python3.5/dist-packages/pip
+    if ! grep -q "$MATRIX_PYTHON " /etc/matrix/run-matrix; then
+        if [[ "$MATRIX_PYTHON" != '/usr/bin/python' ]]; then
+            if [ -d /usr/local/lib/python3.5/dist-packages/pip ]; then
+                rm -rf /usr/local/lib/python3.5/dist-packages/pip
+            fi
+            $INSTALL_PACKAGES --reinstall python3-pip
+            $INSTALL_PACKAGES python3 python3-dev \
+                              python3-pip python3-psycopg2 python3-venv \
+                              python3-setuptools libpq-dev \
+                              python3-lxml python3-treq
+
+            # shellcheck disable=SC2230
+            MATRIX_PIP=$(which pip3)
         fi
-        $INSTALL_PACKAGES --reinstall python3-pip
-        $INSTALL_PACKAGES python3 python3-dev \
-                          python3-pip python3-psycopg2 python3-venv \
-                          python3-setuptools libpq-dev \
-                          python3-lxml python3-treq
-
-        # shellcheck disable=SC2230
-        MATRIX_PIP=$(which pip3)
-    fi
 
-    # recreate the daemon if needed
-    matrix_systemd_daemon
+        # recreate the daemon if needed
+        matrix_systemd_daemon
+    fi
 
     $MATRIX_PIP install --upgrade --process-dependency-links .
     $MATRIX_PIP install --upgrade --force "pynacl>=1.2.1"